<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
		
		<input id="num1"/>
		+
		<input id="num2"/>
		<input type="button" value="=" onclick="jisuan()"/>
		<input id="num3"/>
		<script>
			function jisuan(){
				num3.value=parseInt(num1.value)+parseInt(num2.value);
			}
		
		<script type="text/javascript">
			
			
			<input id="num1"/>
			-
			<input id="num2"/>
			<input type="button" value="=" onclick="jisuan()"/>
			<input id="num3"/>
			<script>
				function jisuan(){
					num3.value=parseInt(num1.value)-parseInt(num2.value);
				}
		
		</script>
		
		
		
			<input id="num1"/>
			*
			<input id="num2"/>
			<input type="button" value="=" onclick="jisuan()"/>
			<input id="num3"/>
			<script>
				function jisuan(){
					num3.value=parseInt(num1.value)*parseInt(num2.value);
				}
				
				</script>
					<input id="num1"/>
					/
					<input id="num2"/>
					<input type="button" value="=" onclick="jisuan()"/>
					<input id="num3"/>
					<script>
						function jisuan(){
							num3.value=parseInt(num1.value)/parseInt(num2.value);
						}/body>
	</body>
</html>
